Method of treating sugar melts



June 25, 1940. D. v. wADswoRTH Er AL' R. 21,498

IETHQD 0F TREATING SUGAR MELTS Original Filed Sept. 27, 1929 Paw 5u araw Triad Wamgglggfafl Aad/faza (lll/W mi Ail @MI El @im Jaula/afd'ranalafed 6064@ THEIR ATTORNEYS ReissuedvJune 25, 1940 UNITI-:D STATESPATENT OFFICE Daniel V. Wadsworth and Leonard Wickenden,

Manhasset, N. Y., assignors to John J. Naugle,

Greenwich, Conn.

Original No. 1,956,260, dated April 24, 1934, Se-

rial No. 395,521,

September 27, 1929.

Renewed 'July 12, 1933. Application for reissue March 3,

1936, Serial No. 86,970

BUlaims.

Our present invention relates to methods of treating sugar melts andsyrups, particularly raw sugar melts, especially washed raw sugarmelts,in such a way as to render the impurities present in such meltsmore readily adsorbable and such melts more readily lterable lthan wherethe same have been kept either in storage or transportatlon, or both,for considerable periods of time, and aims to devise methods of thegeneral character especifled which are simple, which may be easily andconveniently practised and, which are highly successful for thedesignated purposes. Other objects and advantages of the methods of thepresent invention, particularly as exemplified in the followingillustrative embodiments of the same, will in part be' pointed out indetail hereinafter and will in part be obvious to those skilled in theart to which the present invention relates.

In the accompanying specification we shall describe and in the annexeddrawing more or less diagrammatically exemplify, several illustrativeembodiments of the methods of the present invention. It is, however, tobe clearly understood that our invention is not limited to the specicembodiments thereof herein described and more or less diagrammaticallyexemplified for purposes of illustration merely.

Referring to the drawing, in which we have more or less diagrammaticallyexemplified the aforesaid illustrative embodiments of the methods of thepresent invention, the single ngure of the same comprises a schematicarrangement of steps which may be followed in practising the aforesaidillustrative embodiments of the methods of the present invention.

Referring now to the aforesaid illustrative embodiments of thepresentinvention, our starting or raw material is preferably raw sugar havingan average polarization of from about 96 to about 97 degrees. Ordinarilywe use raw cane sugar such as Cuban raw, although, of course, raw canesugar from other sources, as from Puerto Rico, the Philippines, theHawaiian Islands, Santo Domingo and Haiti may be used with equalsuccess, as well as rawv sugars derived from other sources.

We now proceed to wash the raw sugar. This we may do in centrifugals inaccordance with the practice hitherto prevailing. In these centrifugalsthe sugar is washed to a purity of about 99 degrees polarization. It mayhere be stated that the initial unwashcd raw sugars whose polarizationis from about 96 degrees to about 97 degrees' containsQ in addition tothe sucrose, in the case of sugar of 97 degrees polarization, forexample,

about 1 per cent. of invert sugar, 'about 1/2 per cent. of ash, about 1per cent. of organic impurities and about '/2 per cent. of water. 'I'hewashed raw sugar on the other hand having a purity of about 99 degreespolarization, `contains about 1A, per cent, of invert sugar and organicimpurities, about A per cent. ash and about 1/2 per cent. water. v

T'he result of the washing operation is therefore to obtain washed rawsugar of the designated purity and composition and the type of syrupsknown as afinations I'hese ailinations are preferably boiled in a vacuumpan to obtain raw sugar, the final by-product being molasses. The rawsugar obtained from boiling the aillnations is preferably mixed with theincoming raw sugar and Washed in the manner already indicated above.

'I'he next step of the operation is the melting of the washed sugar.This is preferably carried out in the following manner: We prefer tocarry out the melting operation at a temperature of about degrees F.While the sugar may be melted in pure lhot water, We prefer to melt thesame in hotmsweet water, that is, in water which contains some sugarvalues, as the sugar values derived by treating the purifying andflltering media subsequently described to remove the last traces ofsugar therefrom.

In conducting the-melting operation we prefer that the water used formelting, whether ordinarywater or sweet water, shall be substantiallyfree from iron. For this purpose we may treat either the ordinary wateror the sweet water with a suitable reagent, such as a solution ofdisodium phosphate, to precipitate the iron which may afterwards beremoved by decantation or filtration, as desired. We prefer also totreat the ordinary or "sweet water with an agent which will tend toraise its pH and thus lower the hydrogen ion concentration both of thewater used for melting and of the resulting melt.

Accordingly, we use a slight excess of disodium phosphate, which reagentwill therefore serve not only to precipitate iron, but also to raise thepH reading and thus lower the hydrogen ion concentration.

Where, as is preferred, sweet for melting-the washed raw sugar, theamount of disodium phosphate used, both for precipitating iron and forincreasing the pH reading and thus for lowering the hydrogen ionconcentration may range from about 20 to about 50 pounds of thecrystalline disodium salt` per 2000 gallons of "sweet or other waterused for the melting procwater is usedl ossgfmsfwouid correspond to fromabout a toy about sopouuds of the anhydrous salt per zooo gallons ofsweet" or other water used for the melting operation.

i g We `prefer that the density of the resulting melt shall be about 60degrees Brix. more or less. The temperature ofthe hot melt will shortlyfall to about 100 degrees F. It may here be stated, that we prefer thatafter the temperature of the l. melt has been stabilized at about 100F., it shall for this purpo, we prefer to use a chlorine generatingagent, in the form of an aqueous solu- I tion. Ordinarily, however, weuse a ,hypochlorite, preferably a hypochlorite of one of the alkali oralkaline earth metals, such as calcium hypochlorite, preferably in theform of "bleach liquor.

Invtreating the melt with the calcium hypoil chlorite solution orequivalent agent, we may proceed substantially as follows to produce asubstantially colorless product:

Assuming that bleach liquor is the agency to be employed, the bleachliquor for this purpose a may be prepared from solid calciumhypochlorite or chloride of lime by stirring the solid with water untilall of the soluble matter present has gone into solution. ".l'he clearsolution thus obtained may now be decanted from `the insoluble l matter.'I'he proportions used in making the liquid may be vabout pounds ofchloride of lime and about 40 gallons of water. About 18 `gallons of theclear liquor may be run through a -pipe to the bottom of the tankcontaining about U 3000 gallons of say degrees Brix melt. Thisl willcorrespond, for example, to about 19,600 pounds of sugar solids insolution. During this time the average temperature of the melt may bekept at about normal temperature correll spondingto about or 80 degreesF., although higher temperatures may if desired be employed. The mixtureof melt and bleach liquor will be agitated and vthen permitted to standfor about l5 minutes in order to permit the action to be l0A completed.At this point any calcium orv iron present in the melt may again beprecipitated by the addition of a mixture of mono-sodium and disodiumphosphates or by the addition of these phosphates separately or alone.For example, Il to about 3000 'gallons of melt at a density of about 60degrees Brix may be added about 371/2 pounds of disodium phosphate inthe crystalline condition, corresponding to approximately 14% pounds ofanhydrous disodium phosphate and N about 11% pounds of the monosodiumphosphate which is used in the form of the solid. During and after abrief period after the addition of the -monosodium and disodiumphosphates or their equivalents, the melts are briefly and vigorously wagitated. After theprecipitation, corresponding to a defecation oi' themelt, is completed, the agitation may be stopped for a period sumcientto permit the precipitates tc agglomerate and settle. As a result ofthis treatment, the melt 7 is' substantially bleached, or deoolorized,und

sterilized, and the impurities are readily adsorbable and iilterable.

The treatment described above may be repeated several times, after whichthe melt may be further reiined or decolorized. For this purpose itsconcentration is reduced,l as to about 50 to 60 degrees Brix so as tofacilitate the illtering and decolorizing operations. The melt, now ofreduced concentration, is subjected to a treatment with a purifying andiiltering medium as with a suitable amount of a decolorizing carbon,preferably a decolorizing carbon of vegetable origin, such as the highlyactivated decolorizing carbon known to the trade as Suchar.

Ordinarily, where "Suchar" is used, we use an amount of Sucher equal toabout 2 per cent.

of the weight of the sugar solids present in the melt. 'Ihe mixture ofmelt and suspended carbon is thoroughly agitated in a tank. the meltbeing preferably heated to and maintained at a temperature of from aboutto about 200 degrees F., as about or 190 degrees F. 'I'he mixture ofmelt and suspended carbon is now pumped into a suitable illter, such asthe wellknown type of "au iilter. The clear melt coming from the iilteris run through a bag iilter and then through a felt and paper filter toa 'storage tank. From the storage tank it may run into an evaporator,where as is usual, it is desired to increase its density orconcentration as to about 37 degrees Baum corresponding to about 68degrees Brix.

The concentration of the syrup preferably takes place under vacuum, thetemperature being about 110 degrees F. or less. In those cases where thepH reading is corrected in the evaporator it is desirable to addtrisodium phosphate or its equivalent to the syrup when its density hasbeen raised to about 62 degrees Brix.

Where, instead of a refined, substantially color- 5 less syrup, it isdesired to produce rened or granulated sugar directly from thesterilized melt after it reaches its destination, the desired result maybe effected by treating the melt with about 1% to about 2 per cent. ofSuchar or equivalent decolorizing carbon based on the weight of thesugar solids contained in the melt. In other words, the melt, thedensity of which has in this case also preferably been reduced to about50 degrees Brix.- may be treated with carbon in the amounts alreadyindicated. The purified melt so obtained is sent to the evaporating panswhere it is evaporated and refined or granulated sugar obtained bycrystallization under vacuum, four or ve strikes of sugar being soobtainable, the various strikes of sugar being mixed or blended togetherin the production of the refined or granulated sugar which will often beof standard or even superior purity and quality.

This completes the description of the aforesaid illustrative embodimentsof the methods of the present invention. It will be noted that suchmethods are simple, may be easily and conveniently practised and havethe numerous advantages and economies setforth in detail above. It willbe noted that a melt of the desired density, hydrogen ion concentrationand sterile qualities is obtained. From such melt, by means of themethods of the present invention, refined or substantially colorlessSyrups may readily be obtained in an altogether simple and economicalmanner. From such melts may also be obtained refined or granulated sugarof standard or even superior qualities in an altogether simple andeil'ective manner. Other superiorities and advantages of the methods ofthe present invention and of the resulting products, particularly asexemplified in the aforesaid illustrative embodiments of the same, willreadily occur to those skilled in the art to which the present inventionrelates.

It may here be stated that throughout the specication and claims,wherever the term melt" is used, said term is intended to include alsosyrups of any desired degree of concentration, unless a contrary meaningis indicated.

What we claim as our invention is:

l. In the method of treating a sugar syrup or melt to produce asubstantially colorless product, the improvement which comprisestreating washed sugar with an agent of the group consisting of chlorineand the hypochlorites, then with a phosphatic defecating agent, andthereafter adding to theliquid so treated a decolorizing-and filteringcarbon.

2. In the method of treating a sugar syrup or melt to produce asubstantially colorless product, the improvement which comprisestreating washed sugar with a hypoehlorite, then with a phosphaticdefecating agent, and thereafter adding to the liquid so treated adecolorizing and iiltering carbon.

3. In the method of treating a sugar syrup or melt to produce asubstantially colorless product, the improvement which comprisestreating washed sugar with calcium hypochlorite, then with a phosphaticdefecating agent, and thereafter adding to the liquid so treated adecolorizing and filtering carbon.

4. In the method of treating a sugar syrup or melt to produce asubstantially colorless product, the improvement which comprisestreating washed sugar with an agent of the group consisting of chlorineand the hypochlorites, then with one of the phosphates of sodium, andthereafter adding to the liquid so treated a vegetable decolorizing andfiltering carbon.

5. In the method of treating a sugar syrup or melt to produce asubstantially colorless product, the improvement which comprisestreating washed sugar with a hypochlorite, then with one of thephosphates of sodium. and thereafter adding to the liquid so treated avegetable decolorizing and filtering carbon.

6. In the method of treating a sugar syrup or melt to produce asubstantially colorless product, the improvement which comprisestreating washed sugar with calcium hypochlorite, then with one of thephosphates of sodium, and therealt-er with a purifying carbon.

DANIEL V. WADSWORTH. LEONARD WICKENDEN.

